There's no need to split it, we can use the -x compiler flag to build
the .cpp file as Objective-C++, or, as done here, just rename the file.
This allows us to use QVERIFY and friends, giving more precise failure reporting.
Pick-to: 6.4
Change-Id: I6fb1c4454335082c8a39010c5b75c59e6ec6561b
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>